Individuals, corporations, and/or other entities maintaining one or more restricted-access spaces (such as spaces defined within the interiors of land, sea, or air vehicles, buildings, hazardous material containers, controlled-pharmaceutical cabinets, dangerous and/or expensive item storage areas, and/or any other type of area or space where locking mechanisms have been provided to ensure that access to a secure space is limited to authorized individuals) balance the need for maintaining the security of the restricted-access spaces against the difficulty in gaining access to such spaces. Access to restricted-access spaces typically requires that an authorized entity insert a key into a locking mechanism that controls access to a particular restricted-access space.
In addition to ubiquitous key-type locks, relatively recent developments in keyless entry systems enable an individual with a radio frequency (“RF”) transmitter to remotely manipulate a locking mechanism associated with a restricted-access space by transmitting an RF signal to a corresponding RF receiver that is adapted to operate the locking mechanism in response to the receipt of the signal. Unfortunately, physical keys and transmitters can be lost, misplaced, or stolen, thereby significantly increasing the difficulty in gaining access to a restricted-access space by an authorized individual. Accordingly, users and maintainers of restricted-access spaces have a continuing interest in developing self-contained entry systems that do not require authorized individuals to carry keys, transmitters, and/or other devices to gain entry to such restricted-access spaces.